The present invention relates to apparatuses and methods for use in performing spinal surgery and, in particular, to tools and methods of using such tools, especially for implanting a rod for spinal support and alignment.
For many years, spinal osteosynthesis apparatuses have been utilized to correct spinal deformities, injuries or disease. In such procedures, elongate rods are surgically attached to vertebrae of the spine to provide support and/or to realign or reposition certain vertebrae. Such rods are secured to vertebrae utilizing bone screws and other spinal implants. In particular, bone screws with open ended heads are often utilized for such surgery, with the rod being placed into an open end of one or more implants and then the open end or ends being closed or capped to secure the rod to the implant.
Rods utilized in spinal surgery are often bent or formed to support the spine in a desired manner, or to exert a desired corrective or stabilizing force on the spine. Thus, to obtain such a desired alignment, rods must often be forced into open ended spinal implants.
In order to reduce the impact of such surgery on the patient, a desirable approach is to utilize implanting tools and procedures that have a low profile, resulting in less trauma to the body of the patient. Problems arise when implantation tools designed for traditional surgery that is highly invasive are utilized. The tools may be bulky, oversized or have irregular surfaces or protrusions. A projecting actuator arm or fastening member may provide adequate mechanical advantage to force a rod into a head of an implant, but there may be insufficient clearance to use such structure and/or such structure may produce additional trauma or damage to the patient.
Consequently, it is desirable to develop apparatuses and techniques that allow for the securing of a rod to a bone screw or other implant already attached to a vertebra with significantly less invasion into the body of the patient. At the same time, it is desirable to develop such apparatuses and techniques that provide adequate mechanical advantage to force the rod into position within the bone screw and thereafter hold the rod in place during closing or capping of the bone screw head.